1. Field of the Invention
The present invention generally relates to image processing apparatuses, image processing methods, and storage media. More particularly, the invention relates to an image processing apparatus and an image processing method for embedding information into images with the minimum loss in the quality of reproduced images and without increasing the amount of data. The invention also relates to a storage medium for storing the above-described method.
2. Description of the Related Art
One of the techniques of embedding information without increasing the amount of data is to convert the least significant bit (LSB) or the lower two bits of, for example, digital audio data into information to be embedded. In this technique, the lower bits of digital audio data, which do not significantly influence the sound quality, are simply substituted for the information to be embedded. Accordingly, when the digital audio data is reproduced, it is output as it is without restoring the lower bits into the original state. More specifically, since it is difficult to restore the lower bits embedded with information into the original state, and also, since the lower bits do not significantly influence the sound quality, the digital audio data is output while containing information embedded therein.
According to the above-described technique, however, a signal different from the original signal is disadvantageously output, which, to some degree, affects the sound quality if the signal is audio data, or influences the image quality if the signal is video data.